Differential Diagnosis for 25-year-old Female with Right Knee Pain
Single Most Likely Diagnosis
- Patellofemoral Pain Syndrome (PFPS): This condition is characterized by pain around or behind the patella, often associated with activities that put stress on the knee, such as walking, bending, or climbing stairs. The atraumatic onset and worsening of pain with walking and bending are consistent with PFPS.
Other Likely Diagnoses
- Ligament Sprain: Although the patient reports an atraumatic onset, minor sprains can occur without a significant incident. Ligament sprains could cause pain and mild swelling, especially if the sprain is minor and not immediately recognized.
- Meniscal Tear: A meniscal tear can cause knee pain, especially with twisting or bending movements. While it's often associated with trauma, minor tears can occur without a significant incident, and the patient's symptoms could be consistent with a small meniscal tear.
- Tendinitis: Tendinitis, such as patellar tendinitis, can cause knee pain that worsens with activity. The patient's age and the nature of her symptoms make tendinitis a plausible diagnosis.
Do Not Miss Diagnoses
- Septic Arthritis: Although less likely, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. It can present with joint pain, swelling, and decreased range of motion, and the patient's symptoms of pain and mild swelling warrant consideration of this diagnosis.
- Osteonecrosis: Osteonecrosis of the knee can cause sudden onset of pain, usually without trauma. It's less common in young adults but can occur, especially in those with risk factors such as corticosteroid use or excessive alcohol consumption.
- Tumor: Bone or soft tissue tumors around the knee can cause pain and swelling. While rare, these conditions are critical to diagnose early for effective treatment.
Rare Diagnoses
- Osgood-Schlatter Disease: This condition typically affects adolescents and is characterized by pain and swelling below the knee. Although rare in adults, it could be considered in the differential diagnosis, especially if the patient has a history of the condition.
- Complex Regional Pain Syndrome (CRPS): CRPS can cause severe, burning pain in the affected limb, usually after an injury. While the patient reports an atraumatic onset, CRPS is a rare condition that could be considered if other diagnoses are ruled out and the patient's symptoms persist or worsen.